桥梁结构系统识别时的参考通道选择问题

Reference channel selection strategy in system identification of brdige structure

基于环境随机激励技术(NExT)与特征系统实现方法(ERA)的基本思想,明确了采用多参考通道环境随机激励技术与ERA方法联合应用的过程,并重点对NExT/ERA方法应用中参考通道的选择问题进行分析研究。首先,基于模态频率和振型评价指标提出了两个评价准则,可用于识别结果的评价。依据此两评价准则,提出了多参考通道的选择方案。该方法可用于排除不好的通道,尤其对分析节点较多的复杂结构意义会更为突出。最后,通过将方法应用于一著名斜拉桥工程——世界结构控制研究的标尺建筑BILL EMERSON桥的垂直模态识别,验证了所做工作的意义。该项工作可为桥梁结构的系统识别提供有益参考。

Based on basic idea of natural excitation technique （NEXT） and eigen value realization algorithm （ERA）, a solvtion process was formulated adopting NExT/ERA and multiple reference channel. The strategies for determining reference channels were suggested and investigated in the mean time. First, two evaluation criteria concerning modal frequencies and modal shapes were proposed to evaluate the identification results; then, according to the criteria, the strategies for multiple references selection were proposed and discussed herein. The strategy could be used to exclude bad references. In complex structures too many sensors might be on nodes of natural modes, using the proposed strategy many sensors were excluded and only a few necessary sensors were retained. By applying the proposed method to Bill Emerson Bridge well known worldwide as a ASCE benchmark model for structural control problems of cable-stayed bridges, the study nere was proved to be meaningful. The results provided a helpful reference for system identification of general cable-stayed bridges